1. Field of the Invention
The present invention relates generally to a refrigerant filter-drier for removing moisture and other contaminating substances from a refrigerant and, more particularly, to a refrigerant filter-drier for use with a refrigerant recycling, recovery or reclamation device.
2. Discussion
It is well-known that refrigerants, especially chlorofluorocarbons (CFC's), used in vapor compression cooling systems (i.e., refrigeration systems) have a detrimental effect on the ozone layer of the earth's atmosphere when released from the refrigeration system into the environment. To this end, Federal legislation has been exacted, commonly referred to as the Clean Air Act, that has mandated strict requirements directed toward eliminating the release of CFC's into the atmosphere. In fact, after Jul. 1, 1992 it will be a violation of Federal Law to vent any CFC's to the atmosphere and stiff fines and penalties will be levied against violators.
Consequently, the need for effective refrigerant recycling, recovery and reclamation equipment (hereinafter referred to as "recycling equipment") has developed. A natural spin-off from the refrigeration and heating, ventilating and air-conditioning (HVAC) industries, the technology for the new field of recycling equipment has evolved from existing ideas, techniques and equipment known in the refrigeration and HVAC fields. In general terms, recycling equipment collects and reuses the refrigerant of a refrigeration system that has broken down and is need of repair or one that simply requires routine maintenance involving the removal of refrigerant. However, it should be noted that the terms "recover," "recycle" and "reclaim" have significantly distinct definitions in the art and that each definition connotes specific performance characteristics of a particular piece of recycling equipment.
"Recover" means removing refrigerant, in any condition, from a system and storing it in an external container without necessarily testing or processing it in any way. "Recycle" means to clean recovered refrigerant for reuse by separating oil and making a single or multiple passes through devices, such as replaceable core filter-driers, which reduce moisture, acidity and particulate matter that have contaminated the refrigerant. Finally, "reclaim" means to reprocess the recovered and/or recycled refrigerants to new product specifications by means which may include distillation. Chemical analysis of the refrigerant is typically required to determine that appropriate product specifications are met. Thus, the term "reclaim" usually implies the use of processes or procedures available only at a reprocessing or manufacturing facility.
Pursuant to the Clean Air Act, the Environmental Protection Agency (EPA) is charged with promulgating and enforcing regulations which require that recycling equipment be certified for a particular task (i.e., recycle, recover or reclaim). Failure to use certified recycle equipment can result in heavy fines to the violators.
Furthermore, the Air-Conditioning And Refrigeration Institute (ARI) has promulgated standards to define a level of quality for new and reclaimed refrigerants which can be used in new or existing refrigeration and air-conditioning equipment. The standard is intended to provide guidance to the industry, including manufacturers, refrigerant reclaimers, and the like.
It is also well-known in the refrigeration and HVAC fields that contaminated refrigerant can result in the failure of refrigeration system components such as the compressor. Moisture or water vapor of any kind in the refrigerant is a common contaminant. Therefore, removal of moisture and other contaminants from the refrigerant is necessary for the continued efficient operation of the refrigeration system. Thus, it is virtually mandatory for recycling equipment to employ a filter-drier device to clean and dry the refrigerant that is recovered from the system being serviced before the refrigerant is reused. As already mentioned, the term "recycle" requires that recovered refrigerant make a single or multiple passes through devices which reduce moisture.
A filter-drier device most commonly used with recycling equipment includes a replaceable drier block or core that is molded from a desiccant material or a blend of different desiccant materials which, in some instances, include another type of adsorbent material such as activated charcoal. This type of filter-drier is referred to as a "replaceable core filter-drier." The core is tubular in shape and has a longitudinal passageway running through its length to provide for the uniform flow of refrigerant through the filter-drier device. A typical replaceable core filter-drier device 10 currently in use is illustrated in FIG. 1. Replaceable core filter-driers were designed for and have long been used in standard refrigeration equipment in the Refrigeration and HVAC industries. Such driers were attempted to be adapted for a new application in recycling equipment. However, as will be further described, this type of filter-drier was not designed to operate as part of a refrigerant recycling, recovery o reclamation device and is, therefore, not efficient when used with such equipment.
A replaceable core filter-drier is designed to perform as a permanent part of the refrigeration circuit. As shown in FIG. 1, the replaceable core filter-drier 10 includes a heavy, cast steel housing 12 that is closed by a steel plate 14 with a plurality of 3/8 or 1/2 inch diameter bolts 16. The overall length of the filter can vary between 9 and 35 inches. One or more replaceable drier cores 18, weighing approximately 1.5 pounds each, are disposed within the housing 12. Conventional replaceable core filter-drier devices 10 weigh between 12 and 25 pounds, and in some models the filter-drier weighs as much as 50 pounds. The flow of refrigerant through the filter-drier device 10 is indicated by arrows A. When the effective moisture removal capacity of the drier core(s) 18 is exhausted, the entire filter-drier device 10 must be disassembled and the core(s) 18 replaced.
With particular reference to the drier core 18, the flow of refrigerant through the drier core 18 when the filter-drier 10 is installed in a refrigeration circuit is indicated by the arrows B. As indicated by the thickness T of the drier core 10, the refrigerant comes into contact with only a small portion of the desiccant and, therefore only a small portion of the desiccant is utilized to dry the refrigerant on each pass of the refrigerant through the filter-drier device 10. In fact, the thickness T of the desiccant to which the refrigerant is exposed on each pass through the refrigeration circuit may be as little as 1 inch. Consequently, the refrigerant must make numerous passes through the filter-drier device 10 in order to provide contact with a sufficient amount of the desiccant in the drier core 18 and thereby achieve purification to an acceptable level.
Although the replaceable core filter-drier 10 has proved successful in purifying and maintaining the purity of refigerant when it has been installed in the refrigeration circuit of a refrigeration system, it requires a continuous flow of refrigerant therethrough during the system operation to establish and maintain such purity.
A filter-drier for use in recycling equipment, however, must be capable of removing the moisture and other contaminants from the refrigeration circuit being serviced quickly and efficiently and is desired to be light-weight as well. An obvious disadvantage of the conventional replaceable core filter-driers is that they are heavy, bulky and the drier cores are difficult to replace. Another disadvantage of such filter-driers is that they require a continual circulation of the refrigerant in order to reduce the contaminant level in the refrigerant to an acceptable level. In many cases, a service operator may complete the maintenance or repair on the refrigeration system and then be required to wait hours, possibly even days, before the refrigerant is purified to an acceptable level. Therefore, considering the fact that the labor involved in servicing a refrigeration system is a substantial component of the cost of performing the service, it is extremely important that the time required by the service operator to purify the refrigerant be kept at a minimum. In addition, there is a conspicuous waste of energy if the recycling equipment is required to run for hours or days in order to adequately dry the refrigerant to the required level. Further, it is doubtful that recycling equipment utilizing a conventional replaceable core filter-drier could reduce the moisture level in particular refrigerants with high moisture solubility such as R22, R502, R123 or R134a, to meet the ARI Standard 700 specification according to the ARI Standard 740 test procedure. (As yet, R123 and R134a refrigerants have not been included in ARI Standard 700, however their future inclusion is anticipated). It is also doubtful that recycling equipment using the replaceable core filter-drier could reduce the moisture level of R134a to an acceptable level per SAE Standard J2099 when tested under SAE Standard J2210.
Accordingly, it is clear that replaceable core filter-driers are not adequate for drying refrigerant as part of a refrigerant recycling device. In an attempt to address this deficiency, filter-driers employing a loose-fill desiccant have been used, however, very limited success has been achieved. Thus, it is clear that no currently available filter-drier device adequately satisfies the dehydration efficiency requirements for use in a refrigerant recycling device
It is therefore an object of the present invention to provide filter-drier for use in a refrigerant recycling device that is significantly more efficient than filter-driers presently in use with recycling equipment by substantially increasing the amount of desiccant coming into contact with the refrigerant on each pass of the refrigerant through the filter-drier as well as the duration of such contact.
It is another object of the present invention to provide a filter-drier for use in a refrigerant recycling device that is light-weight and readily replaceable.
It is another object of the present invention to provide a filter-drier for use in a refrigerant recycling device that, in all applications, substantially reduces the number of passes of the refrigerant through the filter-drier that are required to achieve the desired purity of refrigerant and, in most applications, requires only a single pass.
It is a further object of the present invention to provide a filter-drier for use in a refrigerant recycling device that will adequately dry high moisture solubility refrigerants, such as R22, R502, R123 and R134a to ARI Standard 700 specifications according to the ARI Standard 740 test procedure.
It is a still further object of the present invention to provide a filter-drier for use in a refrigerant recycling device that is able, in a single pass, to dry R12 refrigerant in automotive A/C applications to SAE Standard J1991 when tested per SAE Standard J1989.
Also it is an object of the present invention to provide a filter-drier for use in a refrigerant recycling device that is able, in a single pass, to dry R134a refrigerant in automotive A/C applications to SAE Standard J2099 when tested per SAE Standard J2210.